거친 표면 형상측정을 위한 큰 등가파장 회절격자 간섭계
Diffraction grating interferometer of large equivalent wavelength for flatness testing of rough surfaces
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Abstract
Images were acquired by the modulation of terahertz electromagnetic signals and compared by modulation frequencies. For the real-time acquisition of images a fast scanning method has been adopted utilizing a galvanometer. The acquired time domain waveforms were transformed into frequency domain data by fast Fourier transformations (FFT). We chose some frequency components to compare the resolution of images. The beam profiles at the focal position were measured by a knife-edge technique. Beam diameter was shown to decrease as the frequency increased. By scanning one- and two-dimensional samples a significant image enhancement was observed with the frequency increment. A nondestructive imaging system using THz electromagnetic pulses was also demonstrated.
참고문헌 (7)
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